#include<bits/stdc++.h>
#define ll long long
#define L x<<1
#define R L|1
#define mid (l+r>>1)
#define lc L,l,mid
#define rc R,mid+1,r
#define OK Ll<=l&&r<=Rr
#define Root 1,1,n-1
#define rep(x,y,z) for(int x=(y);x<=(z);x++)
#define per(x,y,z) for(int x=(y);x>=(z);x--)
#define repn(x) rep(x,1,n)
#define repm(x) rep(x,1,m)
#define pb push_back
#define e(x) for(int i=h[x],y=to[i];i;i=nxt[i],y=to[i])
#define E(x) for(auto y:p[x])
#define Pi pair<ll,ll>
#define ui unsigned ll
inline int read(){int s=0,w=1;char c=getchar();while(c<48||c>57) {if(c=='-') w=-1;c=getchar();}while(c>=48&&c<=57)s=(s<<1)+(s<<3)+c-48,c=getchar();return s*w;}
inline void pf(int x){if(x<0) putchar('-'),x=-x;if(x>9)pf(x/10);putchar(x%10+48);}
using namespace std;
const int N=3e5+5,M=1.1e6+5,inf=(1LL<<31)-1,mod=998244353;
const ll llf=1e18;
inline void add(int &a,int b){((a+=b)>=mod) and (a-=mod);}
inline int Add(int a,int b){return add(a,b),a;}
inline int mul(int a,int b){return 1LL*a*b%mod;}
inline void Mul(int &a,int b){a=mul(a,b);}
inline void red(int &a,int b){add(a,mod-b);}
inline int Red(int a,int b){return red(a,b),a;}
inline int qp(int a,int b){if(!b)return 1;int c=qp(a,b>>1);Mul(c,c);if(b&1)Mul(c,a);return c;}
inline int INV(int x){return qp(x,mod-2);}
int n,m,le[N],re[N];
inline void sub1(){
    while(m--){
        int ty=read();
        if(ty==1){
            int x=read();
            le[x]=read(),re[x]=read()-1;
        }else {
            int a=read(),b=read(),c=read(),d=read();
            ll ans=0;
            if(a<=c){
                rep(i,a,c-1)if(b>=re[i])ans+=b-re[i],b=re[i]+1;
                else b=max(b,le[i])+1;
            }else {
                per(i,a-1,c)if(b>=re[i])ans+=b-re[i],b=re[i]+1;
                else b=max(b,le[i])+1;
            }
            cout <<ans+max(0,b-d)<<'\n';
        }
    }
}
inline void Main(){
	n=read(),m=read();
    rep(i,1,n-1)le[i]=read(),re[i]=read()-1;
    return sub1(),void();
}
signed main(){
	freopen("study.in","r",stdin);
	freopen("study.out","w",stdout);
	int T=1;
	while(T--)Main();
	return 0;
}	